| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 92.5 | 21 |
| 2015 | 92.19 | 21 |
| 2014 | 91.85 | 20 |
| 2013 | 91.48 | 20 |
| 2012 | 91.09 | 21 |
| 2011 | 90.67 | 21 |
| 2010 | 90.23 | 21 |
| 2009 | 89.77 | 21 |
| 2008 | 89.29 | 21 |
| 2007 | 88.8 | 22 |
| 2006 | 88.28 | 24 |
| 2005 | 87.75 | 26 |
| 2004 | 87.19 | 26 |
| 2003 | 86.61 | 27 |
| 2002 | 86.01 | 28 |
| 2001 | 85.36 | 29 |
| 2000 | 84.55 | 30 |
| 1999 | 83.7 | 31 |
| 1998 | 82.81 | 32 |
| 1997 | 81.89 | 32 |
| 1996 | 80.93 | 35 |
| 1995 | 79.93 | 35 |
| 1994 | 78.89 | 35 |
| 1993 | 77.81 | 38 |
| 1992 | 76.69 | 40 |
| 1991 | 75.54 | 43 |
| 1990 | 74.34 | 45 |
| 1989 | 72.72 | 50 |
| 1988 | 70.99 | 53 |
| 1987 | 69.2 | 56 |
| 1986 | 67.35 | 58 |